1 files changed, 67 insertions, 0 deletions
diff --git a/include/util/util.h b/include/util/util.h
new file mode 100644
index 0000000..881b59c
--- /dev/null
+++ b/include/util/util.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * util.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef UTIL_H
+#define UTIL_H
+
+#include "config.h"
+#include "sqfs/predef.h"
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "compat.h"
+
+#if defined(__GNUC__) || defined(__clang__)
+#define UI_ADD_OV __builtin_uadd_overflow
+#define UL_ADD_OV __builtin_uaddl_overflow
+#define ULL_ADD_OV __builtin_uaddll_overflow
+
+#define UI_MUL_OV __builtin_umul_overflow
+#define UL_MUL_OV __builtin_umull_overflow
+#define ULL_MUL_OV __builtin_umulll_overflow
+#else
+#error Sorry, I do not know how to trap integer overflows with this compiler
+#endif
+
+#if SIZEOF_SIZE_T <= SIZEOF_INT
+#define SZ_ADD_OV UI_ADD_OV
+#define SZ_MUL_OV UI_MUL_OV
+#elif SIZEOF_SIZE_T == SIZEOF_LONG
+#define SZ_ADD_OV UL_ADD_OV
+#define SZ_MUL_OV UL_MUL_OV
+#elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG
+#define SZ_ADD_OV ULL_ADD_OV
+#define SZ_MUL_OV ULL_MUL_OV
+#else
+#error Cannot determine maximum value of size_t
+#endif
+
+/*
+  Helper for allocating data structures with flexible array members.
+
+  'base_size' is the size of the struct itself, 'item_size' the size of a
+  single array element and 'nmemb' the number of elements.
+
+  Iternally checks for arithmetic overflows when allocating the combined thing.
+ */
+SQFS_INTERNAL
+void *alloc_flex(size_t base_size, size_t item_size, size_t nmemb);
+
+/* Basically the same as calloc, but *ALWAYS* does overflow checking */
+SQFS_INTERNAL
+void *alloc_array(size_t item_size, size_t nmemb);
+
+/*
+  Convert back to forward slashed, remove all preceeding and trailing slashes,
+  collapse all sequences of slashes, remove all path components that are '.'
+  and returns failure state if one of the path components is '..'.
+
+  Returns 0 on success.
+*/
+SQFS_INTERNAL int canonicalize_name(char *filename);
+
+#endif /* UTIL_H */